Blood stem cell transplantation: from preclinical to clinical models

This introductory statement to the International Symposium "Ten Years of Blood Stem Cell Transplantation in Heidelberg" provides the opportunity to review the experimental work that was necessary to set the stage for the first successful clinical studies to use blood-derived stem cells to treat hemopoietic and other malignancies. The Ulm University research group used the preclinical canine model to systematically and extensively explore the possibilities and limitations of the therapeutic use of blood-derived hemopoietic stem and progenitor cells. It became clear that blood stem cells are physiological elements of the circulating blood, that their concentration can be drastically increased by chemical and biological means, that they do not lose their function during appropriate cryopreservation, and that they can be "purified" and used successfully to restore hemopoiesis after myeloablative conditioning both in the autologous and allogeneic situation. If compared to fetal liver-derived stem cells, there is excellent experimental evidence that fetal liver-derived stem cells may have even more potential in their ability to restore hemopoiesis, and it is evident that much more experimental work is needed.